Largely Mithra again. He was the template for much of what became Jesus. It is also similar to religious practices of the worship of Ra "the sun god". It is really about the shortest day of the year. Remember the Romans had a big empire and when they decided on Christianity they had a lot of beliefs to accommodate.

The use of supernaturalism to manipulate and control people is the world's oldest confidence scheme, it relies on the ritual abuse of children at their most impressionable stage by adults who have themselves been made childish for life by this primitive nonsense.

"Science flies you to the Moon, religion flies you into buildings." - Victor Stenger

"Religion is regarded by the common people as true, by the wise as false, and the rulers as useful." - Seneca the Elder (ca. 54 BCE - ca. 39 CE) Roman rhetorician